The present invention relates to an iron golf club set, more particularly to an iron golf club set by which a golfer can fly each ball to the same direction by approximately the same head turn of each club in hitting when the golfer swings in the same manner with regard to at least seven iron golf clubs of the third to ninth numbers.
Generally, since an iron golf club is a club mainly for getting an accurate flying distance, with regard to golf club numbers, the third to ninth number irons, pitching wedge (PW), sand wedge (SW) and the like which can easily fly up a ball into the air and lessen the run, are employed among club counts in many cases.
Among iron golf clubs, while the club of the third to ninth numbers are often used to hit a ball by full swing, the PW, SW and the like are used to hit in a short distance within about 100 yards more accurately. Therefore, a golfer sometimes controls a shot adjusting the swing power. Accordingly, while the flying distance by the wedge depends on a golfer's skill, the shot ball direction and its flying distance by iron golf clubs of the third to ninth numbers by which a ball is hit by full swing are apt to depend on the efficiency of a golf club itself.
However, in the conventional iron golf club set, a ball tends to easily slice since in the case of a long iron the head turn is late at the impact and easily becomes the state that the face is open even if a golfer swings in the same fixed condition. Conversely, since in the case of a short iron the head turn is early and easily becomes the state that the iron face is closed, the shot ball tends to easily hook.
As a countermeasure for above-described condition, conventionally, there is, for example, a proposition that the condition of head turn should be constant by making the moment My (the head weight.times.the distance of the center of gravity) of club head around shaft axis line of each iron golf club equal respectively (for example, Japanese Patent Laid-Open 54-22241). However, since the head of golf club has a different lie angle in each number, even if the moment My defined by the head weight.times.the distance of the center of gravity is made to be equal with regard to each club, the condition of face turn of head cannot be necessarily fixed as to each club and it was not an essential solution.